Variable Radio Sources in the Corona Australis Cloud

Suters, M.; Stewart, R. T.; Brown, Alexander; Zealey, W. J.

doi:10.1086/117784

Cited by 21 publications

(48 citation statements)

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“…The source underwent a major outburst in the radio continuum while observed by Suters et al (1996). Infrared images show that the object is a 0.6 binary system (Chen & Graham 1993).…”

Section: The Mms 10-13 Groupmentioning

confidence: 97%

“…Infrared surveys have uncovered a small cluster, named the Coronet, of low-luminosity sources embedded around R Cr A (Taylor & Storey 1984;Wilking et al 1986;Wilking et al 1997). More deeply embedded sources have been identified through radio continuum observations (Brown 1987;Suters et al 1996;Harju et al 2001) and millimetre continuum observations Henning et al 1994;Saraceno et al 1996). These young stars drive various outflows which are observed either as Herbig-Haro objects or as molecular outflows (e.g.…”

Section: Introductionmentioning

confidence: 99%

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SIMBA observations of the R Corona Australis molecular cloud

Chini

Kämpgen

Reipurth

et al. 2003

A&A

167

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Abstract. We have mapped the R Corona Australis molecular cloud at 1.2 mm with SIMBA on SEST and detected 25 distinct dust emission peaks. While 7 of them coincide with positions of previously known young stars, 18 are seemingly not associated with any known stellar object. We discuss the nature of individual sources and conclude that there are at least four small concentrations of young objects located along the filamentary shaped cloud. A comparison with C 18 O data hints at the depletion of molecules in some of the cores. Our new results yield some conflicting arguments about whether star formation proceeds from north-west to south-east in the R Cr A cloud.

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“…The source underwent a major outburst in the radio continuum while observed by Suters et al (1996). Infrared images show that the object is a 0.6 binary system (Chen & Graham 1993).…”

Section: The Mms 10-13 Groupmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

SIMBA observations of the R Corona Australis molecular cloud

Chini

Kämpgen

Reipurth

et al. 2003

A&A

167

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show abstract

“…A highly negative spectral index rules out a free-free nature for the emission (Rodríguez et al 1993). For observations made in 1986 and 1992, Suters et al (1996) determined spectral indices in the range of −0.28±0.30 to +1.05±0.17. At least in one epoch the source showed evidence of circular polarization (Choi et al 2009).…”

Section: Ls-rcramentioning

confidence: 99%

JVLA Observations of Young Brown Dwarfs

Rodríguez¹,

Zapata²,

Palau³

2017

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We present sensitive 3.0 cm JVLA radio continuum observations of six regions of low-mass star formation that include twelve young brown dwarfs and four young brown dwarf candidates. We detect a total of 49 compact radio sources in the fields observed, of which 24 have no reported counterparts and are considered new detections. Twelve of the radio sources show variability in timescales of weeks to months, suggesting gyrosynchrotron emission produced in active magnetospheres. Only one of the target brown dwarfs, FU Tau A, was detected. However, we detected radio emission associated with two of the brown dwarf candidates, WL 20S and CHLT 2. The radio flux densities of the sources associated with these brown dwarf candidates are more than an order of magnitude larger than expected for a brown dwarf and suggest a revision of their classification. In contrast, FU Tau A falls on the well-known correlation between radio luminosity and bolometric luminosity, suggesting that the emission comes from a thermal jet and that this brown dwarf seems to be forming as a scaled-down version of low-mass stars.

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“…Brown (1987) carried out VLA observations at λ = 6 cm in 1985, identifying five sources associated with young stellar objects. Suters et al (1996) analyze the radio variability of pre-main-sequence stars using archival VLA (1985VLA ( -1987 and Australia Telescope (1992) data, while Feigelson et al (1998) report on VLA observations at 3.5 cm, taken in 1997. They detect circular polarization toward the class I protostar IRS 5.…”

Section: Protostars In the Coronet Clustermentioning

confidence: 99%

Radio and X-ray variability of young stellar objects in theCoronetcluster

Forbrich¹,

Preibisch²,

Menten³

2006

A&A

144

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The Coronet cluster in the nearby R CrA dark cloud offers the rare opportunity to study at least four "class I" protostellar sources as well as one candidate "class 0" source, a Herbig Ae star, and a candidate brown dwarf within a few square arcminutes -most of them detected at radio-and X-ray wavelengths. These sources were observed with the Very Large Array (VLA) at λ = 3.5 cm on nine occasions in 1998, spread over nearly four months. The source IRS 5, shown earlier to emit circularly polarized radio emission, was observed to undergo a flux increase accompanied by changes in its polarization properties. Comparison with VLA measurements taken in January 1997 allows analysis of longer-term variability. In addition to this radio monitoring, we analyze archival Chandra and XMM-Newton X-ray data of these sources. Three class I protostars are bright enough for X-ray spectroscopy, and we perform a variability analysis for these sources, covering a total of 154 ks spread over more than two and a half years. Also in X-rays, IRS 5 shows the most pronounced variability, whilst the other two class I protostars IRS 1 and IRS 2 have more stable emission. X-ray data is also analyzed for the recently identified candidate class 0 source IRS 7E, which shows strong variability as well as for the Herbig Ae star R CrA for which we find extremely hot X-ray-emitting plasma. For IRS 1, 2 and 5, the hydrogen column densities derived from the X-ray spectra are at about half the values derived with near-infrared techniques, a situation similar to what has been observed towards some other young stellar objects.

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Variable Radio Sources in the Corona Australis Cloud

Cited by 21 publications

References 0 publications

SIMBA observations of the R Corona Australis molecular cloud

SIMBA observations of the R Corona Australis molecular cloud

JVLA Observations of Young Brown Dwarfs

Radio and X-ray variability of young stellar objects in theCoronetcluster

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